I am running a code that uses arcpy.sa.ExtractByMask but it returns: ExecuteError: Failed to execute. Parameters are not valid. ERROR 000824: The tool is not licensed. Failed to execute (ExtractByMask) I know i have spatial analyst licensed and the tool works fine within arcmap itself. Anyone ever come across this? Edit: arcpy.CheckExtension('Spatial') returns 'Available' The code I am trying to run is: # """folder containing only your input rasters and nothing else""" indir = 'D:\Sheyenne\Atmospherically Corrected Landsat\Practice_bands' """absolute path to your mask layer""" mask = 'D:\Sheyenne\sheyenne_area_poly.shp' """create emply list to hold paths to input rasters""" inrasters = [] """populate the list inrasters with all paths to .tif in directory""" os.chdir(indir) for r in glob.glob('*.tif'): inrasters.append(r) """iterate over all input .tif from list inrasters""" for inraster in inrasters: """create a unique name for each output raster""" outraster = inraster.replace('.tif','_clip.tif') """Clip each raster with it's unique name as output""" arcpy.gp.ExtractByMask_sa('inraster','mask', 'output') The snippet when I run the tool in arcmap is: arcpy.gp.ExtractByMask_sa("LT50290282011268PAC01_sr_band1.tif", "sheyenne_area_poly", "D:/Sheyenne/Atmospherically Corrected Landsat/Practice_band_clip/p1") Note that the code is using a loop to execute extract by mask for multiple images while the snippet is the tool for just 1 image. Edit: When I run the extract by mask tool for 1 image in arcmap the snippet returned is: arcpy.gp.ExtractByMask_sa("D:/Sheyenne/Atmospherically Corrected Landsat/Just_bands/LT50300281984137PAC00_sr_band3.tif", "D:/Sheyenne/sheyenne_area_poly.shp", "D:/Sheyenne/Atmospherically Corrected Landsat/Practice_band_clipLT50300281984137PAC00_sr_band3.tif") I then try to run this in python: import arcpy arcpy.gp.ExtractByMask_sa("D:/Sheyenne/Atmospherically Corrected Landsat/Just_bands/LT50300281984137PAC00_sr_band3.tif", "D:/Sheyenne/sheyenne_area_poly.shp", "D:/Sheyenne/Atmospherically Corrected Landsat/Practice_band_clipLT50300281984137PAC00_sr_band3.tif") and the error returned is: ExecuteError: Failed to execute. Parameters are not valid. ERROR 000824: The tool is not licensed. Failed to execute (ExtractByMask)